纳木措沿岸区可培养细菌多样性季节差异及其理化影响因素

Seasonal Variation of Culturable Bacterial Diversity and Its Physicochemical Factors in Coastal Area of Namco Lake on Tibetan Plateau

为开展纳木措水体可培养细菌多样性的季节变化研究,分别于2020年夏季、2021年春季及2021年秋季对纳木措沿岸水体进行采集。采用涂布平板法和平板四区划线法分离纯化水体中可培养细菌,使用16S rDNA基因测序技术结合经典分类方法对所得菌株进行鉴定,并运用相关统计软件进行数据处理与分析。从纳木措3个季节水样中共分离得到1877株可培养细菌,隶属于4门7纲15目26科34属87种。细菌总丰度在夏季最高、秋季最低,而Shannon-Wiener多样性指数、Simpson优势度指数及Pielou均匀度指数均在秋季最高、夏季最低;主坐标分析(PCoA)等分析结果共同表明,春夏间细菌群落结构相似度较高;主成分分析结果表明,对各季节细菌群落分布影响最大的水质理化参数是总溶解固体量;Mantel检验结果表明,各季节间总溶解固体量、温度、化学需氧量和浊度的差异与细菌群落结构的差异呈极显著相关(P<0.001)。研究结果初步探究了纳木措水体可培养细菌物种多样性的季节变化,对青藏高原湖泊生态系统的保护及细菌资源的开发利用具有重要意义。

In order to carry out the study on seasonal changes in the diversity of culturable bacterial communities in water bodies of Namco Lake,water samples were collected in summer 2020,spring 2021 and autumn 2021,respectively.The isolation and purification of bacteria were performed by spread plate method and plate four zone streaking method,respectively.Strains were identified by 16S rDNA gene sequencing technology combined with classical taxonomy method,and the data were processed and analyzed by using relevant statistical softwares.A total of 1877 culturable bacteria strains were isolated from water samples of Namco Lake collected in three seasons,which belong to 87 species,34 genera,26 families,15 orders,7 classes and 4 phyla.The total bacterial abundance was highest in summer and lowest in autumn,while the 3 community diversity indices were highest in autumn and lowest in summer.The results of PCoA and other analyses collectively show that bacterial community structure similarity was high between spring and summer,while it was low between spring and autumn,summer and autumn.The result of the CCA indicates that total dissolved solids was the most influential physicochemical parameter on the distribution of bacterial community in different seasons.The result of the Mantel test indicates that the differences of total dissolved solids,temperature,chemical oxygen demand,and turbidity in different seasons were significantly(P<0.001)correlated with the differences of bacterial community structure.This study initially investigated the seasonal changes in the diversity of culturable bacterial communities in the water body of Namco Lake,which is of great significance for the conservation of lake ecosystems on the Tibetan Plateau and the exploitation and utilization of bacterial resources among them.